In recent years, toasting bread or bagels in homes and restaurants has become an ubiquitous practice typically accomplished using toasters or toaster ovens that are plugged into an ordinary household outlet. The toasting process involves the heating of bread to reduce its water content by about 10-15% through evaporation from an original level ranging from 35-50%. Toasting also caramelizes the surface of the bread, converting and oxidizing complex sugars. As caramelization occurs, volatile chemicals are released producing a characteristic caramel smell. Caramelization is the oxidation of sugar, and is a type of non-enzymatic browning. If sucrose is present, then a sucrose molecule may combine with a water molecule to produce a glucose molecule and a fructose molecule, which increases sweetness. The chemical reaction is: C12H22O11 (sucrose)+H2O (water)=C6H12O6 (glucose)+C6H12O6 (fructose). Additionally, butter, cheese, or other spreads are often placed on bread before or after toasting. Typical cooking times for toasting bread range from approximately 120 to 300 seconds, depending on the level of caramelization required as well as the number of slices of bread simultaneously toasted. Speeding up this process to less than 60 seconds has not been accomplished to date.
Kitchen appliances for homes are generally designed for use with standard 120 VAC in the United States and 220 VAC in Europe. Some motor home vehicles and camping trailers use a standard 12 VDC car or marine battery as a power supply, and convert (as described in U.S. Pat. No. 5,267,134 by Banayan) 12 VDC from the battery into 120 VAC at up to 15 Amps, as in a typical household outlet. The total power delivered to a piece of toast in a toaster or toaster oven is a function of the resistance of the associated heating elements and follows Ohm's Law, but is inherently limited by the power available from the power supply. The total energy required to toast a slice of bread or bagel ranges from about 25 to 50 W-hours. Standard household outlets are able to safely deliver a maximum power of 1800 W, which yields a minimum toasting time of about 50 to 100 seconds for a slice of bread assuming the power is used 100% efficiently.
Toasters and toaster ovens are generally used by consumers as moveable appliances, and are designed to work in standard household outlets. Some special outlets are designed for high power and may deliver more than 15 Amps of current, but these special outlets are considered “dedicated” outlets for fixed items such as large ovens, dishwashers, or refrigerators. Thus, there is currently no method available to reduce cooking time while using a typical U.S. household outlet rated at 120 VAC and 15 Amps. There furthermore is no known method, using even dedicated outlets of high energy capacity, to reduce cooking time, for example, to under 30 seconds to toast a slice of bread.